We use story points instead of man-hours and other time-based units. Let’s see how it works.
Defining the reference
We pick a simple, small user story that everyone understands, as the reference. It would be the definition of 1 story point in our project.
Then, whenever we want to estimate something, we will compare it to the reference. If we believe that it takes twice as much work as the reference, it will be 2sp (two story points); if we believe it takes half the effort, it would be 0.5sp; and so on.
I know what you’re thinking about; the fact that story points are convertible to time. Yes, that’s right. We do it using “velocity”. Can you guess what it is?